The present invention relates to a development and test system for automotive electronics and, more particularly, to a system that provides extra memory for the development and testing of electronic controller modules in automobiles.
Software development for automotive electronics has become a critical task in all product designs. An example is illustrated in U.S. Pat. No. 4,748,843 of Schafer et al. Increased feature content and design complexity have made the evaluation of software programs difficult. Because of this complexity, additional memory is often required throughout the prototype development and evaluation phases of the program. Nowhere is this problem more evident than in the development of electronic modules for automotive applications.
Today, electronic modules are performing a variety of functions. These functions range from electronic instrumentation to basic functions, such as engine and transmission controllers, anti-skid braking systems and airbag modules. This increased emphasis on electronic feature content has made the development of support software very complex. To develop the software needed to operate these electronic modules, additional memory is often needed. The connection of additional memory in such an application is described in U.S. Pat. No. 5,247,446 of Motz et al.
One solution to this problem is to remove the microcontroller from the printed circuit board of the electronic module (mother board) and attach a daughter board comprised of a microcontroller and additional RAM. RAM is used for development and testing because it is easily overwritten. The additional RAM aids in the development of the application software code normally stored in ROM, thus the daughter board is generally referred to as a ROM-Aid board. The ROM-Aid board is additionally interfaced to a personal computer, i.e. PC-station, which can download Object Code to the memory on the ROM-Aid board. Additionally, the electronic module may receive commands from the PC-station.
This solution, however, presents several difficulties. Very often, space available on the mother board is limited and forces the ROM-Aid board to be attached separately. Also, the need for a separate ROM-Aid design board adds cost and assembly time while reducing reliability and complicating the debugging process.
Further, the interface between the main board and the ROM-Aid board is accomplished by either a flex circuit, e.g. a flexible ribbon connector, a special socket or pins. Although pins work in some applications, they are not suited for fine pitch components. Also, some testing involves actual driving of the vehicle and the resultant vibrations may cause the pin connections to fail. The socket design is not suitable for the in-vehicle environment. Soldering is not performed and the module cannot be potted. Therefore flex circuits (or flex strips) are used for in-vehicle calibration purposes.
The use of flex strips, i.e. a flex interconnect, to interface the two board assemblies is standard practice in ROM-Aid testing. The interface to the main board is made via the attachment of the flex strips to the solder pads of the microcontroller. The use of flex strips has been used successfully for a variety of ROM-Aid test modules. However, as the pitch of the microcontroller is reduced, interfacing the microcontroller to the flex interconnect becomes increasingly more difficult. For "fine pitch" components with a large number of pins, this interface is extremely tedious and difficult to work with. In the case of an engine controller, using the ROM-Aid board requires a 60 pin connector.